Line protector



June 7, 1966 H, MaoKENzlE ETAL 3,255,330

LINE PROTECTOR 5 Sheets-Sheet 1 Filed Aug. 30, 1962 JosephjMqc/ngie Glvin E' Paddock INVENTORS June 7, 1966 J. H. MaGKENzlE ETAL 3,255,330

LINE PROTECTOR Sheets-Sheet z Filed Aug. 50, 1962 N R HMac'aengie ddoo mvENToRs am www NWN. Q" M um NNN M. .NHN www SN 5 l l b June# 7, 1966 J. H. MaoKENzu-z ETAL 3,255,330"

LINE PROTECTOR 5 Sheets-Sheet 3 Filed Aug. 50, 1962 INVENTORS FIG., 10

United States Patent O 3,255,330 LINE PROTECTGR .loseph H. MacKenzie, Wilmette, and Alvin F. Paddock,

Roselle, Ill., assignors to Cook Electric Company, Morton Grove, Ill., a corporation of Delaware Filed Aug. 30, 1962, Ser. No. 220,479 18 Claims. (Cl. 20il 124) This invention relates to new and improved line'protectors for telephone service or the like.

One object of the present invention is .to provide a new and improved line protector comprising one or more base v readily be removed from and replaced on the corresponddv ing base module.

Another object is to provide a line protector of the foregoing character in which each over-current protector is adapted to open the corresponding line circuit and ground the line in case of excessive current.

A further object is to provide a new and improved line protector of the foregoing character in which the protector module comprises manually operable plungers or other elements whereby the over-current protectors may be reset, each plunger also indicating by its position when any of the lines has been opened and grounded by the protective operation of the corresponding overcurrent protector, so that maintenance personnel may readily determine which over-current protector needs to be reset.

Another object is to provide a new and improved line protector of the foregoing character Vin which said protector module also comprises means for receiving a test plug or probe whereby test connections may be made with any line and whereby any line may be isolated for testing or maintenance purposes.

A further object is to provide a line protector of the foregoing character which also comprises an alarm circuit for providing an alarm signal when any of the overcurrent protectors has been operated so as to open and ground the corresponding line.

Another object is to provide a line protector of the foregoing character in which any of the protector modules may be unplugged and replaced with a plug-in test module having special means for receiving test plugs or probes.

A Ifurther object is to provide a new and improved line protector of the foregoing character whereby any protector module may be unplugged and replaced with a plug-in test module having special means for opening or isolating any desired line.

Another object is to provide a new and improved line protector in which any of the base modules and any of the protector modules may readily be removed and replaced with new modules, in case defects or faults develop in the old modules.

A further object is to provide a new and improved line protector whereby the base modules and the protector modules may be mounted on a support or stack to any desired height so as to provide protection for a large number of lines.

Still another object is to provide a new andv improved line protector which is highly economical in construction and extremely easy to maintain and service.

Further objects and advantages of the present invention of telephone lines or the like.

will appear from the following description, taken with the accompanying drawings, in which:

FIG. 1 is a perspective View showing a line protector comprising a plurality of base modules and protector modules constructed in accordance with the present invention.

FIG. 2 is a perspective view showing the manner in which the protector modules may be unplugged from the base modules.

FIG. 3 is a horizontal sectional View taken through one of the protector modules.

FIGS. 4, 5 and 6 are cross-sectional views taken generally along lines 4 4, 5 5 and 6 6 in FIG. 3.

FIG. 7 is a longitudinal section, taken generally along a line 7 7 in FIG. 3.

FIG. 8 is a horizontal section taken through one of the base modules.

FIG. 9 is a semidiagrammatic plan view showing a mounting for the 4line protector.

FIG. 10 is a horizontal section showing a test module which may be plugged into the base module in place of any of the protector modules.

FIG. 11 is a horizontal section showing .a special line isolation module which may be plugged into the base module in place of any of the protector modules.

It will be seen that FIG. l illustrates a line protector assembly 20 adapted to provide over-voltage and overcurrent protection for any desired or suitable number The line protector 20 comprises one or more base or receptacle modules 22 and oneor more plug-in protector modules 24. Any desired or suitable number of base modules 22 may be employed. In this case, each of the base modules 22 is Y adapted to receive two of the protector modules 24.

As shown, the base modules 22 are stacked vertically and are mounted on a vertical supporting member 26. Various other suitable racks, frames or the like may be employed 4to support the base modules 22. As already indicated, plug-in connections are provided between the base modules and the protector modules 24 so that any of the protector modules may readily be removed from 'the corresponding base modules 22.

Any of the base modules may easily be removed from the supporting members 26 in case the base module develops trouble andl needs to be replaced. As shown to advantage in FIG. 8, each base module 22 may be mounted on the supporting member 26 by means of two screws 28 which are tapped into or otherwise secured to the supporting member 26. The front end of each screw 28 provides a ground prong 30 which projects forwardly from the base module 22 and is adapted toestablish a ground connection with one of the plug-in protector modules 24. Each screw 28 lextends through a corresponding bore 32 running between the front and rear sides of the base module 22. In this case, a recess 34 is formed in the rear face of the module 22 to receive the supporting member 26.

The illustrated base module 22 comprises a body 36 which may be molded or otherwise formed from a suitable plastic or other insulating material. An insulating cover plate 38 is mounted on the body 36 by means of a plurality of screws 40, or in any other suitable manner.

l5l, 52, 53 and 54, adapted to be connected to the corresponding oice lines. The terminals 41-44 and 51-54 project laterally from the base module 22 through slots 56 formed in the body 36,

As already indicated, the base module 22 acts as a receptacle for two of the protector modules 24. Thus,

the terminals 41, 42, 43 and 44 are in the form of metal strips having portions which connect with contact springs 61, 62, 63 and 64 which are mounted in sockets or receptacle openings 66, 67, 68 and 69 formed in the body 36. Similarly, the terminals 51, 52, 53 and 54 are in the form of metal strips having portions which connect with contact springs 71, 72, 73 and 74 which are mounted in sockets or receptacle openings 76, 77, 78 and 79 formed in the body 36.

To provide for alram Acircuits for the protector modules 24, the base module 36 is formed with two additional sockets or receptacle openings 81, formed in the body 36 above the ground prongs 30. A contact spring 82 is mounted in each of the sockets 81. The contact springs 82 are connected together by means of a metal strip 84 which has a portion 86 extending rearwardly for connection to an alarm bus bar 188. It will be seen that a recess or groove 90 is formed in the rear side of the body 36 to receive the alarm bus bar 188.

To provide more convenient access to the terminals 41-44 and 51-54, it is preferred to provide a swingable mounting arrangement for the vertical supporting member 26 so that all of the base modules 22 may be swung about a vertical axis in one direction or the other, to

bring the terminals 41-44 or the terminals 51-54 to the front. Thus,l the illustrated supporting member 26 is T-shaped in cross section and is provided with a rearwardly projecting ange 94 which may be bolted or otherwise secured to a bracket 96. A vertical bolt or other pivot 98 may be employed to connect the bracket 96 to a horizontal supporting bar or member 100. Thus, the bracket 96 is swingable about the pivot r'98. A suitable detent or locking arrangement may b e provided to retain the lbracket 96 in one Ior more positions. Thus, a ball detent 102 may be mounted on the member 100, for engagement with any one of a plurality of downwardly facing sockets 104 in the bracket 96, lthree such sockets being illustrated. A locking pin may be employed instead of the ball detent 102, if desired. In the illustrated construction, the sockets 104 are so located that the base modules 22 may be retained -in their normal position, facing forwardly, or in either of two displaced positions, angling approximately 45 degrees to the right and to the left.

Each of the illustrated protector modules 24 is provided with a body or housing 110 which may be molded or otherwise formed from suitable plastic or other insulating material. An insulating cover plate 112 is secured to the body 110 by screws 114 or in any other suitable manner.

To form plug-in connections with the base module 22, each protector module 24 is provided with prongs 141, 142, 151 and 152, adapted to be connected, respectively, with the terminals 41, 42, 51 and 52 of the base module 22. The kprings 141, 142, 151 and 152 are adapted to engage the contact springs 61, 62, 71 and 72 of the base module 22. Of course, the base module 22 has two sets of terminals and contact springs, so that the .prongs 141, 142, 151 and 152 may also be engaged with the contact springs 63, 64, 73 and 74.

lu addition, each protector module 24 has a receptacle Contact 130 (FIG. 6) adapted to engage one of the ground prongs 30 on the base module 22. Each protector module 24 also has an alarm prong 182 adapted to make contact with one of the alarm contact springs 82 on the base module 22.

It will be realized that the prongs or contact strips 141 and 142 are normally connected to and hence represent a pair of outside lines. The prongs or strips 151 and 152 flange 187 formed on the prong or strip 141.

are connected to and hence represent the corresponding pair of office lines.

Each of the outside lines is preferably provided with an over-voltage protector 183 which may be of the air gap type. One of the over-voltage protectors 183 is connected between a ground strip or spring 185 and a contact The other over-voltage protector 183 is connected between the ground strip 185 and a contact ange 189 formed on the prong or strip 142. It will be seen that the strip 185 and the iianges 187 and 189 are mounted in the insulating body 110 of the protector module 24. The over-voltage protectors 183 are in the form of cartridges which are frictionally retained between the ground strip 185 and the flanges 187 and 189. Openings 19t) and 191 are formed in the body 110 and the cover 112 of the module 24 to provide for easy removal and replacement of the over- Voltage protector cartridges 183. 1f over-voltage protection is not necessary or desired, the over-voltage protector cartridges 183 may be removed or omitted from the protector `module 24.

Each of the over-voltage protectors 183 may be of the known type providing an air gap 193 between electrodes 195 and 197 which may be made of carbon or similar material. It will be seen that the electrode 195 is connected to the ground strip 135. The electrode 197 is illustrated in the form of a disk mounted within a cupshaped metal housing 199 which is connected to the flange 187 or the flange 189. The electrode 195 is secured within an insulating sleeve 201 which in turn is secured within the outer housing 199. A compression spring 2113 may be provided between the electrode 197 and the housing 199 to bias the electrode 197 against the insulator 291 so as to maintain the electrode 197 in closeproximity to the electrode 195. Any surge of voltage of suicient magnitude will cause a spark or are between the electrodes 195 and 197.

Each of the lines is also preferably provided with an over-current protector 206. Thus, one of the over-current protectors 2116 normally forms a circuit between the connector prongs or strips 141 and 151, but is adapted to open such circuit while also grounding 'the line connector 141 and closing an alarm circuit, in the event that the current owing in the circuit is excessive. The other over-current protector device 296 normally forms a circuit between the connector prongs or strips 142 and'152. 1n this case, each of the over-current protectors 2116 is in the form of a heat coil 298 of the known type in which the coil, wound with resistance wire, is mounted on a shaft or pin 210. The coil 208 has a metal outer shell orV housing 212. The shaft 219 and the shell 212 serve as the electrical terminals of the coil 298. Normally,

- the coil 298 is secured to the shaft 210 by solder or other fusible metal of low melting point. Thus, the coil 2118 is normally -held against rotation on tne shaft 210. However, when excessive current fiows through the coil 2118, the heat generated in the ycoil is sufficient to melt the solder so that the coil becomes freely rotatable on the shaft 210.

It will be seen that the shaft 210 of one of the heat coils 208 is securely mounted on a bar or strip 216 which constitutes an inwardly extending portion of the prong 151. The shaft 210 for the other heat coil 298 is secure- 1y mounted on a strip or bar 217 which constitutes a portion of the prong 152.

It will be seen that the outer shell 212 of each coil 208 is formed with a ratchet wheel or gear 219 which is adapted to be engaged by a ratchet or pawl 221, formed on a corresponding spring leaf or strip 222. It will be seen that each spring leaf 222 is mounted on a movable reset plunger 224 which is slidably mounted in the housing 110. Each plunger 224 has a portion which projects from the outer end of the housing 110. In this case, each spring 222 is connected to the corresponding plunger 224 by means of a tine 22S which extends through a transverse slot 230 in the plunger 224. The tine 228 is at one end of the spring leaf and is bent at right angles thereto.

Each of the plungers 224 is provided with a compression spring 232 which biases the plunger in an outward direction. It will be seen that each spring 232 is received aroundthe corresponding plunger and is compressed between a wall 234 in the housing 110 and a flange 236 on the plunger 224.

To set the over-current protector 206, the corresponding plunger 224 is pressed inwardly so as to slide the ratchet 221 along the gear 219. The ratchet 221 hooks onto the gear teeth so as to retain the plunger 224 in its inwardly pressed position against the biasing action of the spring 232. Y

An electrical connection is made to each of the springs 222 by means of a spring contact or brush 237 which is in slidable engagement with the other side of the spring 222. The contact spring 237 is formed integrally with a flange 239. One of the ilanges 239 is connected to a strip 241 constituting a portion of the prong 141. The other ange 239 is connected to a strip 242 constituting a portion of the prong 142. Thus, one of the ratchet springs 222 is at alll times connected to the prong 141. The other ratchet spring 222 is at all times connected to the prong 142. When the plungers 224 are Apushed inwardly, the ratchet springs 222 are engaged with the gears 219 on the outer shells 2 12 of the heat coils 208 so as to complete circuits to the prongs 151 and 152.

If an excessive current lows through one of the heat coils 208, the heat generated by the coil is suicient to melt the solder between the coil and the shaft 210, so that the coil becomes freely rotatable on the shaft. The force of the corresponding spring 232 is then sufficient to cause the heat coil 208 to rotate until the ratchet 221 is disengaged from the gear 219. This disengagement opens the circuit so as to protect the line against excessive current. At the same time, the line is grounded and an alarm circuit is closed, as will be explained in detail shortly. In

- FIG. 3, the upper ratchet 221 is shown in its disengaged position, while the lower ratchet is shown in engagement with the corresponding gear 219. In a short time, the heat coil 208 will cool off suiciently to solidify the solder between the heat coil and theshaft 210. The over-current protector 206 may then be reset by pushing the corresponding plunger 224 inwardly so as to reengage the ratchet 221 with the gear 219.

Provision is preferably made for grounding the line when the ratchet 221 is disengaged from the gea-r 219. For this purpose, a flange 244 is provided on each spring leaf 222 for engagement wtih a ground spring or flange 246 which is connected to the ground strip 185. When the ratchet 221 is disengaged from the gear 219, the biasing action of the spring 232 causes the flange 244 to move against the ground flange 246. It is also preferred to provide means forcompleting an alarm circuit when the ratchet 221 is disengaged from the gear 219. For this purpose, an alarm spring or'ilange 249 is connected to the alarm prong 182. The tine 228 on the end of the spring 222 is movable against the alarm spring 249 when the ratchet 221 is released from the gear 219. The alarm spring 249 llexes sufficiently to insure positive contact between the tine 244 and the ground ilange 246, while maintaining positive contactv between the flange 228 and the alarm spring 249. Thus, the alarm prong 182 is connected to ground whenever either of the ratchets 221 is disengagedvfrom the gear 219 on the corresponding heat coil 208. This grounding of the alarm prong 182 may be employed to energize a bell, lamp or other signal device in the alarm circuit which may be connected to the prong 182. The sounding of the alarm indicates that the heat coil for at least one of the lines has gone out. Maintenance personnel may then determine which line has gone out by looking for the projecting reset plunger 224. When the trouble in the line has been cleared, the heat coil may be reset by pressing the projecting plunger inwardly.

blades which are movable between the contact spring 237 and the spring 222 so as to open or break into the line at this point, while the corresponding ratchet 221 still remains in engagement with the gear 219 on the corresponding heat coil 208. It will be seen that each plunger 224 has an upper cutaway portion 254 which provides room for the springs 222 and 237 and also communicates with the bore 252.

For various testing purposes, the protector module 24V of FIGS. l-7 may be replaced with a special test module 257, as shown in FIG. 10. Various features of the test module 257 are the same as the corresponding features of the protector module 24. To this extent, the same reference characters have been used in FIG. 10 as in FIGS. 1-7. Thus, the test module 257 retains the plug prongs 141, 142, 151 and 152, as well as the ground receptacle contact 130. As before, over-voltage protectors 183 may be connected between the ground strip 185 and the flanges 187 and 189 on the prongs 141 and 142.

To support the various components, the test module 257 has an insulating body 259. The test module 257 does not have over-current protectors but rather has closed-circuit jacks 261 for receiving suitable test plugs,

which are inserted into the jacks through openings 263 in the body 257. One of the jacks 261 is connected between the prongs 141 and 151. The other jack is connected between the prongs 142 and 152. It will be seen that each jack 261 comprises a contact spring 26S which normally engages a contact member 267. The contact springs 265 of the two jacks are connected to the prongs 141 and 142. The contact members 267 are connected to the prongs 151 and 152. A suitable test plug may be inserted between each spring 265 and the corresponding contact member 267 for opening the line and for making external connections thereto. The over-voltage protectors 183 may be removed or dispensed with, if desired. The test plug may have a cable or lead-out conductors attached to individual circuits within the line protector, making it possible to connect the circuits directly to a test set or board.

FIG. 1l illustrates a different test module 277 which is the same as 'the test module 257, except that shafts 279 are mounted in the body 259 to open the jacks 261. An insulating cam or eccentric 281 may be mounted on the inner end of each shaft 279 to move the corresponding spring 265 away from `the conta-ct member 267. Each shaft has an externally projecting portion 283 which may he rotated manually. The test module 277 may be employed when it is desired to open the lines while maintaining over-voltage Iprotection, or for applications where heat coils are not required.

' With further reference to the protector mdoule 24, it will be realized that any of the protector modules may be unplugged and replaced with another module, if trouble develops in a Ipraticular module. If it is merely desired to open the corresponding pair of lines, the module may simply be removed. It is also easy to remove and replace the base module 22 if necessary.

I-f excessive current ows .in any heat coil 208 so as to release the corresponding ratchet 221, the corresponding plunger 224 will be extended so that the faulty line may be located quickly. When the trouble has been cleared, the heat coil may be reset, simply by pushing the plunger inwardly.

Any desired number of base modules may be stacke on suit-able supporting frames to provide protection for any desired number'of lines. Thus, the modules provide a very versatile and ilexible construction. While the illiustrated lbase modules are ada'pted to receive two protector modules, the construction may readily be adapted to receive only one protector module, or more than two modules.

Various other moditications, alternative constructions and equivalents may be employed without departing from the true spirit and scope of the invention, as exemplified in the foregoing description and defined in the following claims.

I claim:

1. In a line protector.

the combination comprising a base module having a plurality of line terminals, a ground terminai and an alarm terminal,

line contacts on said base module and connected to said line terminals,

a ground contact and an alarm contact on said base module and connected to said respective ground terminal and said alarm terminal,

a protector module disengagebaly connected to .said base module and having a plurality of line contact elements, a ground contact element and an alarm contact element disen-gageably contacting said respective line contacts, lground contact and alarm contact on said base module,

an over-voltage protector disengageably mounted on said protector module and connected between one of said line contact elements and said ground contact element,

an .over-current protector mounted on said protector module and having a shaift with a heat coil mounted thereon,

said shaft constituting one terminal element of said over-current protector,

a gear on said heat coil,

a movable ratchet engageable with said gear,

a movable reset lplunger supporting said ratchet,

a spring biasing said reset plunger in a direction for moving said ratchet away from said gear upon the release of said heat coil,

a contact brush engaging said ratchet,

said brush constituting the other terminal .element vof said over-current protector,

means connecting the terminal elements vof said overcnrrent lprotector to :said line contact elements on said protector module,

a ground contact member connected to said ground contact element Aand engageable by said ratchet upon release of said ratchet from said gear,

and an alarm contact member connected to said alarm contact element and engageable by said ratchet upon release of said ratchet from said gear,

said plunger having a test bore therein aording access to said ratchet and said brush.

. 2. In a line protector,

the combination comprising a base module having a pair of line contacts,

a protector module disengageably mounted on said base module and having a pair of line contact elements disengageably contacting said line contacts on said base module,

a heat coil on said protector module and having `a shaft connected to one of said line contact elements,

a ratchet member having a ratchet thereon,

a gear on said heat coil,

said ratchet being movable into engagement with said gear,

a movable reset member supporting said ratchet member [for movement of said ratchet into and out of engagement with said gear,

a spring biasing said reset member in a direction for moving said ratchet away from said gear,

and a spring contact member engaging said ratchet member and connected to the other of said line contact elements,

said reset member having a test bore therein affording access to said ratchet member and said contact spring.

3. In a line protector,

the combination comprising a pair of line contacts,

a ground contact,

an alarm contact,

a heat coil having a shaft connected to one of said line contacts,

said heat coil having a gear thereon,

a ratchet member having a pawl thereon engageable with said gear,

a slidable reset plunger supporting said ratchet member for movement of said pawl into and out of engagement with said gear,

a spring biasing said reset plunger in a direction for moving said pawl out off-engagement with said gear,

a contact spring engaging said ratchet member and connected to the other of said line contacts,

a ground contact member connected `to said .ground contact and engageable by said ratchet member upon release of said pawl from said gear,

and an alarm contact member connected to said alarm `contact and engageable by Vsaid ratchet member upon release of said pawl strom said gear,

said reset plunger having a .test opening ytherein a-f- Afoi-.ding access to said ratchet member and said contact spring. l

d. In a line protector,

the combination ycomprising a pair of line contacts,

'a heat coil having a shaft connected to one of said `line contacts,

a gear on said heat coil,

a ratchet engageable with said gear,

a reset member supporting said ratchet Vfor movement into and out of engagement with said gear, Y

'and means for connecting :said ratchet to the other o said line contacts,

said reset member having a test opening therein aii'ording `access to said ratchet.

5. In a line protector,

the combination comprising a pair of line contacts,

a ground contact,

an alarm contact,

'a heat vcoil having a shaft connected to one of said line contacts, i

a gear on said heat coil,

a ratchet engageable with said gear,

means connecting said ratchet to the other of said line contacts,

a movable `reset 'member supporting said ratchet,

means for 'biasing said ratchet away from said gear upon release of said heat coil,

a ground contact member connected to said ground contact and engageable by said ratchet upon release of said ratchet from said gear,

and means operable by said ratchet for connecting said alarm contact to said ground contact upon release of said ratchet from said gear,

said reset member having a bore therein affording access to said ratchet.

6. A 'line protector device comprising means connectable to an outside line, means connectable to an inside line, an over-current protector means interconnected between said outside line means and inside line means, said protector means including resetable means responsive to an vover-current condition in said lines and movable automatically into a visually observable over-current position, and means defined in said resetable means providing a passageway through said resetable -means to said outside line means and inside line -means so that a test probeV can be inserted into said passageway means tn test the condition of at least one of said lines.

7. A line protector device comprising Ameans connectable to an loutside line, means connectable to an inside line, an over-current protector means interconnected between said outside line means and inside line means, said protector means including movable means normally disposed` in a first visually detectable position and operable in response to an overload condition in said lines to move automatically into a second visually detectable over-current position, and opening means defined in said movable means providing access to said outside line means and inside line means throughsaid movable means, said opening means accommodating a test probe sothat the probe can be-inserted into said movable means to engage at least one of said line means irrespective of the position in whi-ch the movable means is disposed.

8. A line protector device comprising means connectable to an outside line, means connectable to an inside line, an over-current protector means interconnected between said outside line means and inside line means, said protector means including heat sensitive means responsive to an over-current condition moving from a first to a second over-current position, spring biasing means, movable means coacting with said heat sensitive means and movable manually into a latched connection with said sensitive means and movable under the control of the spring biasing means into a visually detectable over-current position in response to operation of said sensitive means resulting from an over-current condition in said outside and inside line means, and opening means defined in said movable means providing access to said outside line means and inside line means through said movable means, said opening means accommodating a test probe so that the probe can be inserted into said movable,4 means to engage at least one of said line means irrespective of the position in which the movable means is disposed.

9. In a line protector, the combination comprising a base module having a plurality of line terminals and a ground terminal, line contacts on said base module and connected to said line terminals, a ground contact on said base module connected to said respective ground terminal, a protector module diseng-ageably connected to said base module and having a plurality of line contact elements, a ground contact element disengageably contacting said respective line contacts, and ground contact on said base module, an over-current protector mounted on said protector module and interconnected between at least two of.

said line contact elements, said over-current protector including resetable means movable from a normal visually detectable position to a second visually detectable position in response to an overload condition in at least said two line contact elements, and opening means defined in said resetable means providing access to said two line contact elements through said resetable means from outside of said protector module, said opening means accommodating a test probe for engaging at least one of said two line contact elements irrespective of the position of the resetable means.

10. A protector module adapted to detachably connect to a base module having a plurality of line and ground terminals respectively connected to a plurality of line and ground contacts, said protector module including a plurality of line and ground contacts adapted to engage the line and ground contacts of the base module, respectively, an over-current protector interconnected between at least two of said line contact elements, said over-current protector including resetable means movable from a normal visually detectable position to a second visually detectable position in response to an overload condition in at` least said two line contact elements, and opening means defined in said resetable means providing access to said two line contact elements through said resetable means from outside of said protector module, said opening means accommodating a test probe for engaging at least one of said two line contact elements irrespective of the position of the resetable means.

11. A line protector base module adapted to form with other base modules a generally elongated stack, said base module comprising means for detachably supporting said base module to a suitable support, a generally flat housing made of insulating material, a plurality of means defined in said housing for accommodating a plurality of terminals of a protector module, a plurality of integral electrically conductive means each of which includes a terminal portion extending transversely of the stack and a contact portion coacting with said accommodating means to electrically engage a terminal of said protector module, and grounding means including a prong portion for coacting with said protector module and connecting means for detachably securing said grounding means to said suitable support.

12. A line protector 'base module comprising a housing,

means in said housing Lfor receiving a plurality of terminals of a protector module, electrically conductive means including a plurality of contact portions that respectively coact with said receiving means to engage the terminals of said protector module, said conductive means being connectable to communication lines, and means for detachably supporting said base module to a suitable support including a grounding probe extending outwardly of said base module -for engagement with saidprotector module, said grounding probe including a detachable connecting portion adapted to coact with said suitable support.

13. A line protector base module comprising a housing made of insulating material, means in said housing for receiving a plurality of terminals of a protector module, electrically conductive means including a plurality of contact portions that respectively coact with said reeciving means to engage the terminals of said protector module, said -conductive means being connectable to communication lines, means for detachably connecting the base module to a suitable support, opening means extending through said housing, and ground probe means disposed in said opening means and having a protector module engaging end and a portion adapted to be detachably connected to said suitable support. i

14. In a line protector, a protector module comprising a housing made of insulating material, at least one -pair of electrically conductive terminals adapted to be reecived in opening means of a base module, one of said terminals having a wiper contact, an over-current sensitive device electrically interconnected between said terminals, said device including an element electrically connected directly to the other of said terminals and a current responsive element having a latching means, and movable plunger means including an electrically conductive leaf spring biased away from said heat responsive element, said leaf having a portion in slidable electrical engagement with said wiper contact irrespective of the position of said plunger means and having a ratchet adapted to be latched by said latching means, the ratchet and latching means being disengaged in response to operation of the current responsive element to electrically disconnect said electrically conductive terminals.

15. A protector module comprising a first line terminal, a second blade line terminal, a third terminal respectively adapted to electrically engage terminals of a base module, said blade terminal having a Ywiper contact extending generally transverse to the plane of the blade terminal, an over-current sensitive device electrically connected directly to the first line terminal and including a current sensitive rotary latching means .electrically connected to said first line terminal, movable plunger means including an electrically conductive leaf, means for resiliently biasing said plunger means away from said latching means, said leaf including a portion underlying said wiper contact so as to be in sliding engagement with said wiper contact irrespective of the position of said movable plunger means and, further, including a cut-away portion dening a ratchet for engaging said rotary latching means and defining a tine means adapted to engage said third plunger means to electrically disconnect said rst and second line terminals.

16. A protector module comprising a rst line terminal, a second blade line terminal, a Kground terminal respectively adapted to electrically engage terminals of a base module, said blade terminal having a Wiper contact eX- tending generally transverse to the plane of the blade terminal, au over-current sensitive device electrically connected directly to the iirst line terminal and including a current sensitive rotary latching means electrically connected to said iirst line terminal, movable plunger means including an electrically conductivev leaf, means for resiliently biasing said plunger means away from said latching means, said leaf including a portion in sliding engagement with said wiper contact, a struck-away ratchet for engaging said latching means, and a struck-away transversely extending tine, the ratchet and latching means being disengaged under the control of said biasing means in response to operation of the over-current device thereby to electrically disconnect said first and second line terminals and 4electrically connect said second blade terminal and said ground terminal.

17. The protector of 4claim 16 wherein said leaf includes an opening that facilitates manual resetting of the plunger means and latching lmeans and is defined 'by the struck-away ratchet and tine.

18. The combination of a line protector base module comprising a housing,vmeans in said housing for receiving a plurality of terminals of a protector module, electrically conductive means including a plurality of contact portions that respectively coact with said receiving means to engage the lterminals of said protector module, said conductive means being connectable to communication lines, means for detachably supporting said base module to a suitable support including a grounding probe extending outwardly of said base module for engagement with said protector module, said grounding probe including a detachable connecting portion adapted to coact with said suitable support, in a line protector, a protector module comprising a housing made of insulating material, at least one pair of electrically conductive terminals adapted to be received in opening means of a base module, one of said terminals having a wiper contact, an over-current sensitive device electrically interconnected between said terminals, said device including an element electrically connected directly to the other of said terminals anda current responsive element having a latching means, and movable plunger means including an electrically conductive leaf spring biased away from said heat responsive element, said leaf having a portion in slidable electrical engagement with said wiper contact irrespective of the position of said plunger means and having a ratchet adapted to be latched by said latching means, the ratchet and latching means being disengaged in response to operation of the current responsive element to electrically disconnect said electrically conductive terminals.

References Cited by the Examiner UNITED STATES PATENTS 783,995 2/1905 Cook 200-115 786,005 3/ 1905 Cook 200-1 15 810,914 1/1906 Cook 200-124 1,089,167 3/ 1914 Wacker. Y 1,238,728 8/1917 Parker 200-115 1,678,800 7/1928 Baker 200-124 2,125,126 7/ 1938 Rivers. 2,150,635 3/ 1939 Ridgers 200-124 2,517,506 8/1950 Riggs 200-44 2,546,824 3/1951 Koliss 200-115 2,632,039 3/1953 Hammerly et al. 3l'71 19 2,703,830 3/1'955 Miller 20C-51.1 2,866,033 12/1958 Dillon 200-116 X 2,959,774 11/ 1960 Arrasmith 317-99 FOREIGN PATENTS 695,292 8/ 1953 Great Britain.

709,114 5 1954 Great Britain.

345,051 4/ 1960 Switzerland.

OTHER REFERENCES German application 1,065,502, Setpember 17, 1959 (3 pp. spec., 1 sht. dwg.).

BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

1. IN A LINE PROTECTOR. THE COMBINATION COMPRISING A BASE MODULE HAVING A PLURALITY OF LINE TERMINALS, A GROUND TERMINAL AND AN ALARM TERMINAL, LINE CONTACTS ON SAID BASE MODULE AND CONNECTED TO SAID LINE TERMINALS, A GROUND CONTACT AND AN ALARM CONTACT ON SAID BASE MODULE AND CONNECTED TO SAID RESPECTIVE GROUND TERMINAL AND SAID ALARM TERMINAL, A PROTECTOR MODULE DISENGAGEABLY CONNECTED TO SAID BASE MODULE AND HAVING A PLURALITY OF LINE CONTACT ELEMENTS, A GROUND CONTACT ELEMENT AND AN ALARM CONTACT ELEMENT DISENGAGEABLY CONTACTING SAID RESPECTIVE LINE CONTACTS, GROUND CONTACT AND ALARM CONTACT ON SAID BASE MODULE, AN OVER-VOLTAGE PROTECTOR DISENGAGEABLE MOUNTED ON SAID PROTECTOR MODULE AND CONNECTED BETWEEN ONE OF SAID LINE CONTACT ELEMENTS AND SAID GROUND CONTACT ELEMENT, AN OVER-CURRENT PROTECTOR MOUNTED ON SAID PROTECTOR MODULE AND HAVING A SHAFT WITH A HEAT COIL MOUNTED THEREON, SAID SHAFT CONSTITUTING ONE TERMINAL ELEMENT OF SAID OVER-CURRENT PROTECTOR, A GEAR ON SAID HEAT COIL, A MOVABLE RATCHET ENGAGEABLE WITH SAID GEAR, A MOVABLE RESET PLUNGER SUPPORTING SAID RATCHET, A SPRING BIASING SAID RESET PLUNGER IN A DIRECTION FOR MOVING SAID RATCHET AWAY FROM SAID GEAR UPON THE RELEASE OF SAID HEAT COIL, A CONTACT BRUSH ENGAGING SAID RATCHET, SAID BRUSH CONSTITUTING THE OTHER TERMINAL ELEMENT OF SAID OVER-CURRENT PROTECTOR, MEANS CONNECTING THE TERMINAL ELEMENTS OF SAID OVERCURRENT PROTECTOR TO SAID LINE CONTACT ELEMENTS ON SAID PROTECTOR MODULE, A GROUND CONTACT MEMBER CONNECTED TO SAID GROUND CONTACT ELEMENT AND ENGAGEABLE BY SAID RATCHET UPON RELEASE OF SAID RATCHET FROM SAID GEAR, AND AN ALARM CONTACT MEMBER CONNECTED TO SAID ALARM CONTACT ELEMENT AND ENGAGEABLE BY SAID RATCHET UPON RELEASE OF SAID RATCHET FROM SAID GEAR, SAID PLUNGER HAVING A TEST BORE THEREIN AFFORDING ACCESS TO SAID RATCHET AND SAID BRUSH. 